Plaster board



Feb. 2 1929.

C. W. UTZMAN l703'183 PLASTER BOARD Original Filed Aug. 12, 1922 lira/ Zvr. 6' 10219220920. 1/ 2mm,

Patented Feb. 26, 1929.

UNITED STATES PATENT OFFICE.

CLARENCE W. UTZMAN, OF WILMETTE, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO UNITED STATES GYPSUM COMPANY.

rLAs'rnn BOARD. I

Application filed August 12, 1922, Serial No. 581,362. Renewed March 4, 1927;

This invention relates to plaster board or the like. Plaster board is usually employed as a wall covering in substitution for lath and plaster..

Among other objects, the invention is intended to supply a protected edge for plaster board which shall be of .neat appearance, se-

, cure and durable.

' v The invention resides in the novel constructions, combinations and methods, hereinafter described or claimed, for carrying out the above stated object and such other objects as will hereinafter appear.

In the drawings:

Fig. 1 is a fragmentary perspective showing an end of the plater board and a protected edge thereof embodying this invent-ion,

Fig. 2 is a cross section through the line 3-3 of Fig. 1, showing the covering sheets at an intermediate-stage in the formation of the illustrative protected edge, and

Fig. 3 is a section on the line 2-2 showin tle finished form of the illustrative protected e ge.

theplaster oard is of plaster or the like, with or without admixture of other ingredients. The body 5 has a top cover sheet 6 and a bottom cover sheet 7, 'referably of heavy paper or the like adhered to the face of the body. One of the covering sheets, the sheet 7 in the illustrative instance, is folded at its margin 8 so as substantially to cover the edge of the plaster body 5. To-facilitate the folding of the margin 8 the sheet 7 may be scored at 9 along the line uponwhich the margin 8 is to be folded.

.The margin 8 is intended to. protect the lowermost corner of the plaster-body, and the folding up'of said margin upon the edge of the body providesa rounded lower corner for the board, as indicated at 10. To protect the uppermost corner of the plaster body, and to provide a similar or somewhat similar rounded upper corner for the board, a margin 11 of the top covering sheet is folded down toward the extreme edge of the margin 8. The margins 8 and 11 may contact and engage each other so as to form a substantially continuous protective closure over the upper and lower corners and the edge of the board as indicated in Figs. 1 and 3.

The marginal portion of the top covering sheet may be feathered or tapered from its extreme edge to a point somewhat beyond the Referrin to the drawings, the body 5 ofv intended adjacent corner of the board, by ehamfering or beveling its under surface, as indicated at 12 in Fig. 2, so as to facilitate the folding down of said margin and to make it more pliable for moulding the rounded corner and for adhering the plaster of the edge and-for engaging, if desired, with the margin 8.

wherein the folded up margin 8, of the bottom covering sheet extends substantially across the edge of the plaster body, the top covering sheet has only sufiicient margin to extend beyond the plaster body, in the condition shown in Fig. 2, approximately the thickness'of the covering material; and, the under surface of the sheet being chamfered to a point beyon'dthe intended corner, the thin feathered edge or margin 11 thus provided may easily be moulded down over the corner to round the same, to give substantially the. same effect as the rounded lower corner of the board. This may be done in the process of manufacturing the board by passing the same, while the plaster is still plastic, in con-. tact with a grooved pulley or shoe'or other moulding device to press down or mould the upper corner to secure the desired rounded corner effect, similar to that of the lower corner, as will be well understood.

The margin'8 is preferably provided at intervals lengthwise with deformations affording a mechanical bond with the body material. For instance these deformations may consist of the burr-like projections 14 formed at intervals along the margin 8, by making In'the preferred construction illustrated, I I

ragged apertures in the material of the marlayer on the bottom covering sheet 7, the

margin 8 of,which may be folded upon and in adhering contact with the edge of the plastic layer; and the top covering sheet may then be applied; and the dge portion or short margin 11 thereof may e folded down (over the upper corner of the body) toward the extreme edge of the margin 8 of thebottom sheet, as shown in the drawings; both sheets 6 and 7 adhering to the plastic body material I ing, which will facilitate the bending of said margin over the corner of the body and the adherence of the edge portion thereof to thebody material, the thin edge being substantially merged with the body material and the extreme edge of the margin 8, and being more firmly held by the body material. The tapering or beveling of the margin 11' may be conveniently accomplished by passing the same over grinding means such for instance as rapidly rotating emergy Wheels. This grinding roughens the under surface of the marginal portion of the sheet and enables it to be more substantially united with the body material. The aforesaid deformations in the margin 8 of the bottom covering sheet, may, if desired, be formed preliminarily to the folding of said margin upon the edge of the body material, in which event said deformations may be caused to embed in or interengage with the plastic bod material by effecting a slight spreading o the material when the margin is folded against the edge thereof; or the said deformations may be made in the margin 8 after the margin is folded upon the edge of the body material and while the latter is still in plastic state, so as to allow the plastic material to spread through the apertures of the margin and engage against the for turning up the margins of the lower sheet and pressing them against the edges of the plastic material, and deforming the margin 8 to secure anchorages in the plastic material as aforesaid, and for beveling the margin 11 of the top covering sheet and folding the same over the corner of the plastic body material, the latter step being preferably carried out as the last step of the process.

Having described my invention,.I claim A plaster board comprising, in combination, a body of plaster or the like; covering sheets on the opposite faces of said body; one of said sheets having a folded margin protecting a corner of said body and substantially covering an edge of said body; said corner being rounded, the other sheet having a ta-' pered or feathered marginal portion adhering to the opposite corner and extending to- Ward the first mentioned margin; said 0pposite corner being rounded to conform substantially to the first mentioned corner.

In testimony whereof,gI have signed my name to'this specification.

' CLARENCE. W. UTZMAN. 

